1. Field of the Invention
This invention relates generally to apparatus for controlling the delivery of fuel to an internal combustion engine, and pertains more particularly to a pivotal air door or velocity blade that possesses the desirable characteristics of both carburetion and injection devices for introducing fuel and air into a combustion chamber of an internal combustion engine via a reciprocable intake valve that is controlled as to both its lift and duration.
2. Description of the Prior Art
Air doors, or velocity blades as they sometimes are called, have been used previously, both in connection with carburetion and also in connection with fuel injection systems. Although air doors have functioned satisfactorily when used in fuel injection systems, the cost of an injection system is quite appreciable, and this has militated against any extensive use of such systems insofar as I am aware. Two examples of fuel injection systems utilizing air doors are found in U.S. Pat. Nos. 4,079,718, issued on Mar. 21, 1978 to Siegfried Holzbaur for "Fuel Injection System" and U.S. Pat. No. 4,134,379, issued on Jan. 16, 1979 to Gerhard Stumpp for "Fuel Injection System." The two patented systems operate on a fuel injection principle at all times.
Insofar as air doors having been used in association with carburetors and when they perform a venturi action, illustrations of such uses are contained in U.S. Pat. No. 1,611,347, issued on Dec. 21, 1926 to Albert E. Hartwell for "Carburetor" and U.S. Pat. No. 3,291,464, issued on Dec. 13, 1966 to Rudolph L. Hammerschmidt for "Carburetor Having Adjustable Precision Fuel Metering Means." These two patents, however, disclose carburetor arrangements that do not utilize therein fuel injection principles.